1. Technical Field
The present invention relates generally to valves for controlling the flow of fluid and, more particularly, to a valve which is controlled using a master key such that only an authorized person is able to control the valve.
2. Background Art
As well known to those skilled in the art, in many industries, pipes are widely used to carry material such as liquid or gas. Generally, valves are provided on the pipes to control the flow of fluid. Various kinds of valves have been devised and are used. Such valves serve to turn on or off the flow of fluid or adjust the flow rate.
Particularly, the present invention is a technique pertaining to valves provided with handles so that fluid passage through the valves is controlled by rotating the handles. The general construction of such a valve is well known, therefore a detailed explanation is deemed unnecessary.
Meanwhile, a valve was proposed in Korean Utility Model Registration No. 388434, which is entitled “ON/OFF VALVE HAVING HANDLE STOPPER”, by the applicant of the present invention.
The present invention is based on this technique and improves it. The technique of Korean Utility Model Registration No. 388434 will be described in brief herein below as a prior art related to the present invention. The usefulness of the present invention will be appreciated in light of this description.
FIG. 1 is a schematic sectional view showing the construction of the on/off valve according to the conventional technique. The construction of the on/off valve will be explained herein below.
The on/off valve according to the conventional technique includes a main body 1, which has an inlet and an outlet therein, and a rotator 30, which is installed at the center in the main body 1 and has therein a fluid passage corresponding to the inlet and the outlet. The on/off valve further includes a handle 2, which is coupled to the rotator 30 at a position spaced apart from the upper surface of the main body 1 by a predetermined distance, and serves to rotate the rotator 30. Furthermore, the conventional on/off valve further includes a handle stopper 10. The handle stopper 10 includes a stop pin 13, which is supported by an elastic means 12 placed in a seating hole 11 formed in the upper surface of the main body 1. In addition, the handle stopper 10 further includes a push lever 15, which contacts the upper end of the stop pin 13 and is inserted into a vertical hole 14 that corresponds to the seating hole 11 and is formed in the handle 2.
In the conventional on/off valve having the above-mentioned construction, the push lever 15 protrudes upwards from the upper surface of the handle 2. Therefore, when an operator pushes the push lever 15, the stop pin 13 is moved downwards, thus releasing the handle 2, which has been in the locked state.
However, because the conventional on/off valve has a structure such that the push lever 15 is exposed outside, anyone can control the valve. Therefore, the conventional on/off valve is problematic in that there is a likelihood of inappropriate control of the valve attributable to carelessness. In particular, in an industrial field requiring a high level of safety, there is the probability of a serious safety hazard due to carelessness or intentional manipulation by an outsider.